The system of energy which drives and controls the nature of the pressure, winds, and climatic belts of the Earth’s surface, with solar radiation as the heat source, and terrestrial radiation as the sink. Mechanical energy is expended by the ‘engine’ in the form of atmospheric processes. Haine and Marshall (1998) J. Phys. Oceanog. 28, 4 characterize the poleward heat transport as a diffusion by baroclinic eddies. Barry et al. (2002) Nature 415 regard the baroclinic zone as a heat engine which generates eddy kinetic energy by transporting heat from a warmer to a colder region.